1. Field of the Invention
The present invention relates to an electronic device suitable for use in, for example, transmitter-receiver unit of a portable telephone.
2. Description of the Prior Art
A conventional electronic device will now be described with reference to FIGS. 6 to 8. A box-shaped frame 21 formed by a metallic plate is provided with side walls 21a which define an inside space having upper and lower openings and is also provided with mounting legs 21b formed in the side walls 21a. 
On a printed circuit board 22 is formed a conductive pattern 23, to which various electric parts (not shown) are soldered to constitute a desired circuit.
The printed circuit board 22 is inserted from below the frame 21 into the inside space defined by the frame 21 and is secured to the frame by bending the mounting legs 21b inwards.
The mounting legs 21b and the conductive pattern 23 are soldered together at 24 to earth the conductive pattern 23 to the frame 21.
As shown in FIG. 8, the electronic device such as a transmitter-receiver unit constructed as above is then mounted onto such as a mother printed circuit board 25 of the portable telephone and is used.
In this case, the electronic device is surface-mounted onto the mother printed circuit board 25. More particularly, first the electronic device is put on a predetermined place of the mother printed circuit board 25 and thereafter a cream solder is applied to each corner portion between a conductive pattern 26 on the mother board 25 and the frame 21 of the electronic device.
Then, the mother board 25 and the electronic device are put on a belt (not shown) and are conveyed to a reflow treatment device to ensure soldering between the conductive pattern 26 on the mother board 25 and the frame 21.
In the conventional electronic device, the frame 21 is mounted merely by being put on the mother board 25, so at the time of surface mounting there is a fear that soldering may be done in a dislocated state of the electronic device from a predetermined position on the mother board due to vibration or shock. Therefore, the quality of the device may deteriorate.
Further, since soldering is performed at corner portions between the frame 21 and the mother board 25, there arises the problem that at the time of surface mounting the solder spreads along the corner portions and hence becomes thinner, thus resulting in the soldering being not effected to a satisfactory extent.
According to the first means adopted by the present invention for solving the above-mentioned problems there is provided an electronic device comprising a metallic frame having side walls and leg portions projecting downward from the side walls and a printed circuit board having through portions, the through portions being each constituted of a through hole or cutout portion, and wherein the printed circuit board is put on the underside of the frame in a partially outwardly projected state of the printed circuit board from the side walls, and the leg portions of the frame are inserted into the through portions of the printed circuit board and are projected downward from the underside of the same board.
According to the second means for solution adopted by the invention, the leg portions are tightly fitted in the through portions.
According to the third means for solution adopted by the invention, the leg portions each have a tapered portion which is wider gradually from its base end portion toward its tip end portion.
According to the fourth means for solution adopted by the invention, the printed circuit board has gap portions contiguous to the through portions.
According to the fifth means for solution adopted by the invention, the gap portions are each adjacent to a side end portion of the printed circuit board and partially opened in the side end portion.
According to the sixth means for solution adopted by the invention, the printed circuit board has a conductive pattern in proximity to the leg portions.